Evaluation Of Farmland Ecological Suitability In Danjiangkou City

Land suitability evaluation which refers to the evaluation of suitability degree to the special use land is the important foundation work to establish the general land use planning. Through land suitability evaluation, we can timely and accurately report the present situation and problem of the land resource, then can use reasonably the land resources and protect the national economy sustainable development. The land adaptability of the water resources area not only related to local economic and social development, but relate to the whole basin sustainable development and the water quality degree. Therefore, the evaluation of land ecosystem adaptability in water source area is an important foundation work which relates to the management of the local land resource and national economy sustainable development.Basing on the studying on the theory and the technology of the land suitability evaluation, and mainly centering on the land resources utilization and the protection of the ecological environment of the water resource region, the paper proposes the effective ways and means of the land suitability evaluation in water resource area with GIS. The paper discusses the present situation and problem of the land utility in water resource area in Danjiangkou City, and finds the method which uses GIS to accomplish the space superposition analysis to the topography, soil conditions, traffic conditions, hydrological conditions, social conditions and present situation of land-use, and evaluates the suitability of the following land use types: farmland, garden, woodland and pasture and give the measurements of optimization and adjustment of the land use structure. Thus can improve the science and reliability of the land suitability evaluation, and promotes the management of the land resource and the economic and social sustainable development of water resource in Danjiangkou City. The results are as following:(1) The level of the soil situation of the farmland is not high as a whole in Danjiangkou City, the rice soil and moisture soil which are better for plant growth cover a total area of 11067 hm2 that account for 5.2% of the total land areas. To change the present situation, we should strengthen the work of cultivating the soil and regenerating the soil. According for the index of the landform, the farmland of slope greater than 25 degrees covers area of 10500 hm2 that account for 4.9% of the total land areas. The farmland of the height above 1200m covers area of 383 hm2 that account for 0.2% of the total land areas. This shows the local geography situation is difficult to cause soil and water erosion. So in another word, the reasons which cause seriously soil erosion in Danjiangkou City are the soil conditions, vegetation status and social conditions. (2) There is cultivated land by 21821 hm~2 in Danjiangkou City. Through the suitability evaluation, the paper concludes that there is cultivated land by 27019 hm~2 which fits to cultivate, so it is an important work to enhance the protection of cultivated land. The result also shows that there is 4874 hm2 land which is not suitable for cultivated land, and the land of slope greater than 25 degrees needs to stop cultivating and to develop forest and grass. At the same time, we should build a high standard of farmland to accomplish the target of high input and output, and reduce the number of agricultural production, so reduce the utility of the fertilizer and pesticide.(3) There is woodland by 154921 hm2 in Danjiangkou City. According to the evaluation results, there is land which suit for planting by 78906 hm~2, It shows that Danjiangkou City's forest coverage rate is higher than expected, that maybe is the reason why Danjiangkou Water Resource Area can maintain good water quality and ecological environment. But there is woodland which isn't suitable for forestry by 26885 hm~2 that account for 17.4% of the present woodland area. In which there are woodland by 20778 hm~2, shrub woodland by 5619 hm~2, and open forest land by 488 hm~2 need to adjust.(4) There is garden by 16678 hm~2 in Danjiangkou City. In the evaluation results, there is farmland suitable for developing garden by 87409 hm~2, so it has more chance to develop gardening. In addition, from the climate and the advantage of the existing resources, it can also meet the local reality. The analysis shows that the land which should be adjusted is almost the existing woodland.(5) There is pasture by 19257 hm~2 in Danjiangkou City. In the evaluation results, there is farmland which suits for planting grass by 19342 hm~2 is equal to the existing areas. However considering the plant growth and soil and water erosion, there is pasture by 7846 hm~2 which should be adjusted to other use type, at the same time there is other land use types by 7931 hm~2 which should be adjusted to pasture. The region where is suitable for pasture with severe soil and water erosion doesn't fit for the development of forestry, where grazing should be prohibited to facilitate to protect soil and water in the mountain.Combing Analytic Hierarchy Process with Geographic Information System, the paper designs innovatively and studies the land ecosystem suitability evaluation methods of Riverhead Reservoir Area in theory, method and technology. The result shows that the constructed farmland ecosystem suitability evaluation system is scientific and feasible, and the evaluation results is consistent with the practical situation of land use the in Danjiangkou City, and explores the land development potential. So the result can be the base for land-use planning in future.